NK
yep
Size: a a a
2016 November 18
NK
VT
What's ColumnA here
VT
And what's 'row'
NK
Block 0 store just one column, just like TinyLog
VT
ClickHouse do not store data like that
VT
Blocks are perpendicular to columns
VT
Block size is pretty simple: it's just how many rows will be loaded and processed as a whole
NK
Thank you
VT
Hope that was helpful :)
NK
I got it
NK
the block is like row-store database？
VT
VT
Data is stored as a columns
VT
But when you need to read and process the data
VT
Let's say you're processing 2 columns with 1.000.000 rows
VT
Then data will be read and processed from disk in blocks of 'block size'
VT
So it will read 65536 rows from 3 separate columns and then they will be processed in one process call
VT
Why we need that is because we can't process all the data because we need to divide processing
VT
Better now?